For those who decide to make telescopes it is a fascinating hobby. Telescopes are usually designed to perform particular kinds of work. In general, for visual work, low-ratio telescopes with their wide fields are useful for comet seeking, variable star work, and the like. The higher ratios are used in planetary study, double star observations, and in other fields where high powers and fine definition are required. Anyone can make telescopes though, don’t be scared off by technical terms.
From the experience gained by those involved in amateur telescope making, it has been found that the most practical and popular instrument for amateur use is the 6-inch f/8 Newtonian reflector. Its concave mirror is 6″ in diameter and its focal length 48″. The delicate task of parabolizing the mirror, while not easy, is not beyond the ability of a careful worker. The 4-foot focal length makes for comfortable observing, and with a low-power eyepiece, the field of view is a trifle over one degree in diameter - more than twice that of the full moon. When you make telescopes the benefits are extremely rewarding.
The magnifications that may be employed permit of a modest size of mounting, which can be made portable. Such a telescope should reveal stars of magnitude 12.8, as compared with the 6th-magnitude limit of the unaided eye, and the 9th-magnitude limit of the average small binocular.
This telescope will show the divisions in Saturn’s rings; surface markings on the moon little more than a mile across should also be visible. Amazing what suddenly opens for you when you decide to make telescopes!
The purchase price of such an instrument of professional make is necessarily high, and many an amateur feels compelled to do without it. Of course, many engaged in amateur telescope making feel that their mirrors are inferior to the professionals’, but this is not necessarily true. It has been frequently demonstrated that mirrors of professional make will seldom stand up to a test, because it is impossible for the professional optician to spend sufficient time on the mirror without losing money, whereas the amateur can, if he will, devote all the time and care necessary to produce a mirror of admirable figure.
Upkeep is slight for those who chose to make telescopes at home. The reflective aluminum coating of the mirrors of a reflector is subject to deterioration from dust and the elements admitted by the open tube, but given the same protection when not in use that is accorded a refractor, at least two years of service should be realized before the aluminizing job need be repeated.
For those involved in amateur telescope making, the task is time consuming but extremely rewarding. Good luck! Go for it- make a telescope!
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